diff --git a/appengine/flexible/pubsub/requirements.txt b/appengine/flexible/pubsub/requirements.txt
index 60f9fdda307..4a1ea40790a 100644
--- a/appengine/flexible/pubsub/requirements.txt
+++ b/appengine/flexible/pubsub/requirements.txt
@@ -1,3 +1,3 @@
 Flask==1.1.1
-google-cloud-pubsub==1.1.0
+google-cloud-pubsub==1.4.2
 gunicorn==20.0.4
diff --git a/appengine/standard_python37/pubsub/requirements.txt b/appengine/standard_python37/pubsub/requirements.txt
index 18a1c3ee2db..5b84bb0278b 100644
--- a/appengine/standard_python37/pubsub/requirements.txt
+++ b/appengine/standard_python37/pubsub/requirements.txt
@@ -1,4 +1,4 @@
 Flask==1.1.1
 google-api-python-client==1.7.11
 google-auth==1.11.2
-google-cloud-pubsub==1.1.0
+google-cloud-pubsub==1.4.2